From owner-freebsd-mips@FreeBSD.ORG Mon Sep 16 17:42:36 2013 Return-Path: Delivered-To: freebsd-mips@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTP id F16AF9D2; Mon, 16 Sep 2013 17:42:35 +0000 (UTC) (envelope-from adrian.chadd@gmail.com) Received: from mail-wi0-x22e.google.com (mail-wi0-x22e.google.com [IPv6:2a00:1450:400c:c05::22e]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 56ED72F63; Mon, 16 Sep 2013 17:42:35 +0000 (UTC) Received: by mail-wi0-f174.google.com with SMTP id hj3so3785989wib.13 for ; Mon, 16 Sep 2013 10:42:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:cc:content-type; bh=6otCeGZRCzfHe4R25sh8Cx2Adad027bAk9wOyZLQlH8=; b=abiJLZTHxf/2t5Xe5dN+LS+98OzgyhU6heXbAZ+qQydQNjoj3HK9AHqyBx/QKIT2RQ tbJIpyunnMtJV6JKAecL8Zkaqg8BzFD4JvhiNNpfvAgWaFnriyvNEfSIPGh5z5hsHqWV hHkjO3wGrcjt6nXsELdLajkTt4sw8DPaeu6upesjSzjCmZTapfMcQMvfJIt006iUPRdF Y/+OhEOWpBk1G49AN0zRWncGdvU4xodtDuG1t5CDkXEIGW079y97XhdyB+uyHZrlY9zn 2fGtzYnRzmnlhBjMYS9l8tQeippAUCpyjKMCrAc8GOhpsPsUjG1Sr4NyBjIk/IeNz0EL SszQ== MIME-Version: 1.0 X-Received: by 10.180.109.132 with SMTP id hs4mr14357955wib.46.1379353353618; Mon, 16 Sep 2013 10:42:33 -0700 (PDT) Sender: adrian.chadd@gmail.com Received: by 10.216.73.133 with HTTP; Mon, 16 Sep 2013 10:42:33 -0700 (PDT) In-Reply-To: References: Date: Mon, 16 Sep 2013 10:42:33 -0700 X-Google-Sender-Auth: oPxTnYi33LDe5qpcOUsv_RcmCpA Message-ID: Subject: Re: random MIPS TLB exceptions? From: Adrian Chadd To: Juli Mallett Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.14 Cc: "freebsd-mips@freebsd.org" X-BeenThere: freebsd-mips@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Porting FreeBSD to MIPS List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 16 Sep 2013 17:42:36 -0000 I unfortunately didn't save the console log :( I'll make sure I do next time. For ref, twas an RSPRO w/ ath wifi hardware. Running a read-only AP image. No mounted USB disks or normal running system. It was in the raw xmit code path and the code itself and around it made no sense from a crash perspective - registers pointed at correct values / addresses. A reboot of exactly the same kernel didn't show a problem. I'll try to reproduce exactly what I did yesterday (which was start it up, then do some console serial IO whilst doing network IO) But yeah, it's tricky to track down. This was less about "this is what the problem is" and more a solicitation for further information from people who may have seen random crashes and rebooted.. -adrian On 16 September 2013 10:16, Juli Mallett wrote: > On Mon, Sep 16, 2013 at 1:09 AM, Adrian Chadd wrote: > >> Hiya, >> >> I just saw a random panic on MIPS in kernel code where it shouldn't occur. >> It hasn't happened after a reboot. >> >> Has anyone else seen occasional TLB exceptions? >> > > Not enough information. There is no "MIPS" kernel and no "MIPS" platform, > so it's hard to make sense of the problem space here. My instinct would be > that sporadic issues of this kind could often be caused by a driver or > similar, so it would be helpful to know what hardware you're using, what > kernel you're running, and what kind of workload is going on. It could be > something that others simply haven't hit for circumstantial reasons (say, a > problem related to swapping), or based on what drivers and hardware are > in-use. (Is there wireless involved? Doesn't that bring in all kinds of > timers and occasional beacons that could be received? That kind of thing > seems like it could result in sporadic crashes.) > > Did you get any kind of backtrace? Was it actually a "TLB exception" > (which has a specific meaning), or do you really just mean you're seeing > random panics and that you think the TLB might be implicated? What kind of > TLB exception? Load, store, modify? > > I haven't seen anything like what you describe, I don't think, but I'm > also not sure what you're describing. Hopefully we can track this down. > > Thanks, > Juli. >